Radiation Therapy. A Swedish Story.

"Physics is my hobby, and I consider myself privileged to earn a salary doing it. Working in medical physics is my way of giving back to society for that privilege," was something Luciano Bertocchi—Director of the IAEA's International Center for Theoretical Physics and promoter of the College of Medical Physics in Trieste—loved to repeat to his students (myself included).

Physics was also a hobby for Rolf Sievert, who inherited a considerable fortune from his father, who passed away when Rolf was just 17. Unsure of which direction to take in life, Rolf first dropped out of his medicine studies at the Karolinska Institute and later left the engineering program at the Royal Institute of Technology (KTH). Ultimately, he graduated in physics from Uppsala University (after all, all great physicists pass through Uppsala, right?)

The meeting with G?sta Forssell

Freshly graduated, Rolf embarked on a self-financed journey to the United States, where—in his own words—he wanted to witness "the greatest developments in physics." However, one cannot run away from destiny; what changed young Rolf Sievert's life forever was the chance meeting with Carl Gustaf "G?sta" Forssell, a fellow Swede, in New York.

It was the summer of 1920.

This, you see, is a story of connections—and Sweden is a small country. G?sta, in fact, had also spent time in Uppsala, and now he was the head of Stockholm's Radiumhemmet, which was one of the most important research centers for the emerging field of radiotherapy in the world.

Years earlier, G?sta had been an assistant to Professor Thor Stenbeck—yes, that Stenbeck, who, together with fellow physician Tage Sj?gren, successfully treated a woman's skin cancer using X-rays in 1899, marking the first documented curative radiotherapy in history.

Yes, the very first radiotherapy treatment in the world was performed in Sweden! And it will not be the last "first ever in the world" breakthrough in radiotherapy coming from Sweden—as you will see.

Knockin' on Radiumhemmet's Door

Once back in Stockholm, Rolf knocked on the door of Radiumhemmet and said to G?sta, "I do not need a salary; what I need is a room." Although Radiumhemmet did not really have a physics laboratory, that wasn’t a problem—Rolf Sievert could finance everything himself. So he got the room and purchased all the necessary equipment out of his own pocket. Needless to say, this earned him the title of Director of the Physics Laboratory.

This is also a story of entrepreneurship. Rolf did not intend to sit back and enjoy his title; he had many ideas. The one I like the most was his initiative to set up a mobile physics laboratory, equipped with portable instruments, which he would offer on-demand to other hospitals—for a fee (if you are curious about Rolf's many initiatives, I do recommend the books by Bo Lindell)

Meanwhile in Uppsala

One year later, in 1926, another important figure (for this story) entered the world stage: Theodore "The" Svedberg, a professor at Uppsala University, received the Nobel Prize for Chemistry. I don't know for sure, but I like to imagine that Rolf attended one of Theodore's classes when he was a student there.

As the turbulent times of World War II passed, The Svedberg founded—in Uppsala—the Gustaf Werner Institute for research in nuclear physics, nuclear chemistry, biology, and medicine.

The Institute was named after textile magnate Gustaf Werner, who donated its primary research instrument, a synchrocyclotron. Unlike Sievert, Svedberg did not have the financial means to establish his own laboratory.

The Svedberg Laboratory: how a small laboratory can make a big impact

Why is this important? Well, the Gustaf Werner Institute—later renamed The Svedberg Laboratory (TSL)—has played a crucial role in an incredible series of events in the history of radiation therapy.

As reported by the Swedish newspaper Svenska Dagbladet, now-Professor Rolf Sievert was present at the inauguration of the proton facility for cancer treatment, in 1955. Rolf could not miss this milestone — just as when he was a young graduate, he maintained his keen interest in witnessing "the greatest developments in physics."

It was 1957 when, at the Gustaf Werner Institute, Sweden delivered the world’s first clinical proton therapy treatment. (In Berkeley in 1954, protons had been delivered in a research setting, but Uppsala was the first to establish proton therapy in a clinical setting.)

The Professor from Lund

Proton radiation from the Werner Institute’s synchrocyclotron was subsequently used for radiation therapy with what is called "stereotactic localization," a method previously used in brain surgery. In these procedures, the patient’s head was fixed in a frame that, when used with X-rays to locate tumors or other pathological changes, defined coordinates.

As Bo Lindell narrates in his book The History of Radiation, Radioactivity, and Radiological Protection, another key figure in this story was a relatively young physicist from Uppsala, B?rje Larsson (yes, Uppsala strikes again!). And B?rje had a brilliant idea.

There was one world expert in the field of stereotactic localization—who had also graduated from Karolinska and, I imagine, was influenced in his passion by Radiumhemmet and the work of Rolf Sievert—and who now was a professor in Lund: neurosurgeon Lars Leksell. Professor Leksell had developed stereotactic methods for precise treatment using X-rays.

From protons to the Gamma Knife

B?rje, known for his inventiveness and energy, was working at the Werner Institute when he contacted Lars with a clear question: "Is proton radiation from the cyclotron suitable for stereotactic radiation treatment?" The neurosurgeon’s reaction, we know today, was positive, marking the beginning of a collaboration between Larsson and Leksell, who began to perform "surgery" using proton radiation instead of a surgical knife.

Although the experiments were successful, the complexity of using a proton accelerator posed challenges. Lars and B?rje then began to search for alternative approaches. Eventually, they conceived the idea of stereotactic irradiation using gamma radiation from a large number of gamma-emitting sources arranged in directed channels around the patient’s head—a device that Leksell called the "Radiation Knife."

B?rje Larsson and Kurt Lidén were tasked with constructing this device, with the intention of installing it at Karolinska Sjukhuset’s neurological clinic, where Leksell had been Professor of Neurosurgery since 1960.

The device was produced at the Motala workshop and was ready in 1966.

Radiotherapy: a Swedish story

Sweden is truly an incubator of innovation in radiation therapy: the first-ever radiation therapy treatment in 1899, the incredible impact of Rolf Sievert on modern radiation protection, the first clinical proton therapy in Uppsala, and the invention of stereotactic radiosurgery culminating in the Gamma Knife.

As I wrote at the beginning, the story of radiation therapy is truly a story about Sweden.

About me

I’m passionate about radiation and radiation safety, and I lead these efforts at a top MedTech company. My experience includes working with the European Commission and international physics laboratories, where I developed my expertise in nuclear physics (without causing any explosions!). With a PhD in applied nuclear physics, I’ve published research in peer-reviewed journals and enjoy crafting content that makes complex topics in science, safety, and security accessible and engaging—because everyone loves a good science story!

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Some photos of my time at The Svedberg Laboratory (2006 - 2011)

The The Svedberg Laboratory has not only served as a center for proton radiation therapy, but also as a research facility for both fundamental and applied nuclear physics. In addition to its proton beam lines, the laboratory featured two neutron beam lines: one delivering 175 MeV quasi-monoenergetic neutrons and another providing an atmospheric spectrum of neutrons from a spallation target. The TSL ceased operations in 2016 and is now undergoing decommissioning.

I worked at TSL from 2007 to 2011, where I was responsible for the Medley spectrometer installed on the 175 MeV QMN beamline. The results from my scientific work there have been instrumental in validating the Monte Carlo code MCNP6.